Breast Cancer Coverage from Every Angle

Comparing First-Line Treatments in Triple-Negative Breast Cancer

By: Kayci Reyer
Posted: Friday, August 23, 2019

A combination treatment of atezolizumab, cobimetinib, and paclitaxel or nab-paclitaxel was found to have a safety profile that is consistent with the safety profiles of the individual components, according to research from the phase II COLET trial, which was presented at the 2019 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract 1013). Overall response rates were found to be similar between the two combination treatment groups as well.

“We investigated the efficacy and safety of [atezolizumab, cobimetinib, and paclitaxel or nab-paclitaxel] in patients with metastatic triple-negative breast cancer, as this combination may target multiple cancer immune escape mechanisms simultaneously,” noted Adam Brufsky, MD, PhD, of the University of Pittsburgh Medical Center, and colleagues.

The study included 125 evaluable patients who were randomly assigned to receive 840 mg of intravenous atezolizumab on days 1 and 15 plus 60 mg of cobimetinib daily from days 3 to 23 plus either 80 mg/m2 of intravenous paclitaxel on days 1, 8, and 15 (arm A, n = 63) or 100 mg/m2 of nab-paclitaxel on days 1, 8, and 15 (arm B, n = 62), all on a 28 day cycle until toxicity or disease progression. At a median follow-up of 6.5 months, 21 patients in arm A and 20 patients in arm B had begun new or adjuvant taxane therapy, and 9 patients in arm A and 6 in arm B experienced disease progression within 12 months. Overall, patients with PD-L1–positive disease experienced improved overall response rates and progression-free survival.

The majority of all study patients experienced an adverse event grade 3 to 5 (69% arm A/70% arm B), and all patients had an adverse event of some degree. Serious adverse events occurred in 47% of arm A and 43% of arm B.

Disclosure: The study authors’ disclosure information may be found at

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